
Hidden hazards in plastic materials and packaging: Are you aware of the hazard?
Highlights
- Plastics are the most popular materials used in packaging.
- The recycling triangle sign is located on the plastic packaging and indicates the type of plastic used during manufacturing.
- Heat is the most threatening factor that causes the release of harmful substances from plastics.
- Developed countries have drastically reduced or banned serving hot food in plastic containers.
- Lifestyle changes in terms of plastic material use should be a part of our lives to reduce the harmful effects on the environment and human health.
Products made of plastic materials are in every part of our lives today. Their usability, lightness, cheapness and flexibility features made them widely used in household goods and tools, car parts, laboratory materials, toys, food and beverage containers, packaging materials, doors and windows. However, the use of plastic materials is also associated with harmful outcomes. Because of their harmful effects on health, some of them have been removed from the production of food packaging and banned, and some have been restricted.
How do plastic materials affect health?
Plastic containers have become one of the most popular food packaging materials. However, in case of wrong/hazardous material selection and if proper storage conditions are not provided, there will be a transition of various chemical substances into the food, leading to serious health problems, especially cancer.
When food or liquid contact with plastic packaging, a chemical transition called “migration” (1) takes place and causes serious health problems.
Pure plastic, which is a hard substance, has no harmful effects when taken orally, other than causing obstruction in the digestive system or mechanically damaging it. Chemicals are added to plastic, which is widely used as a food packaging material, especially to provide softness and flexibility. These chemicals can pass from plastic packaging to foods. Developed countries that are aware of the risk are trying to restrict the use of plastic materials in the food sector. Some countries have completely banned serving hot foods in plastic containers.
What are the factors that increase the harmful effects of plastic packaging?
- The transition of harmful chemicals in plastic packaging to foods depends on the chemical properties of both the plastic and the food.
- The way of packaging, temperature, contact with UV rays, storage time and storage conditions are factors that can affect the consumers' health.
- Oily and acidic foods, heating in a plastic cup, and drinking hot drinks in a plastic cup are the factors that increase the transition of chemical substances from plastics to foods.
What are the different types of plastic materials used in packaging?
Chemicals included in the plastic packaging are indicated with a number in the recycling triangle symbol. The majority of the time, the recycling triangle sign is located at the bottom of the plastic material and they are numbered from 1 to 7. All plastic packaging materials from numbers 1 to 7 are recyclable.

Phthalates (Polyethylene terephthalate (PET) or (PETE))
Phthalates (2) are chemicals used to make plastic materials soft. The term pet bottle comes from here. It is widely used in plastic water bottles, energy drinks, ketchup bottles and other sauce bottles and also jam and jelly jars. Children are the most vulnerable group of people because phthalates may have been used in plastic toys and this is not legally required to be stated in some countries.
Phthalates are a group of chemicals. Since special names can be written on the packaging instead of the generally known phthalate name, everyone should know the phthalate compounds. These are:
- Diethyl hexyl phthalate (DEHP-Prohibited in the European Union and USA)
- Dibutyl phthalate (DBP)
- Benzyl butyl phthalate (BBF)
- Diisononyl phthalate (DINP)
- Diisodecyl phthalate (DIDP)
- Di-n-octyl phthalate (DNOP)
A chemical substance called nonylphenol ethoxylate (NFE) can be released from a plastic container produced with PET/PETE. It is a group of chemicals used in food packaging, laundry detergents, household and personal cleaning materials, the textile industry, paints and pesticides. When they enter the body, they mimic the oestrogen hormone. They cause the formation of hormone-dependent cancers or the rapid proliferation (proliferation definition: increase in number of something) and growth of existing cancers.
High-density polyethylene (HDPE)
The 2 code inside the recycling triangle shows that the plastic material contains high-density polyethylene (3) or in abbreviations HDPE. Similar to phthalates, a substance called nonylphenol (4), which acts like the oestrogen hormone, can be released from plastic containers and facilitate the growth and proliferation of existing tumours.
However, high-density polyethylene (HDPE) is still considered one of the safest groups of plastics. It is especially used in the plastic packaging of cleaning materials. It is also used in milk bottles, juice bottles, and yoghurt packaging.
Polyvinyl chloride (PVC-V)
Vinyl chloride (5), which has been proven to be carcinogenic, can pass-through containers. For this reason, its use in food packaging is prohibited. At the same time, Di-2-Ethylhexyl adipate (DEHA) and phthalates, which are hormone disruptors and possible carcinogens can also pass-through containers.
PVC is most commonly used in door and window systems. It is not recommended for use in hot countries. PVC is known as toxic plastic. It has been proven to cause liver cancer (6) in workers working in this sector.
PVC can be found in the structure of the cling film. For this reason, a high level of care should be taken not to be in contact with food during its use.
Di-2-Ethylhexyl adipate (DEHA) is also presented in the structure of the cling film, which is a hormone disruptor and possible carcinogen.
Low-density polyethylene (LDPE)
A substance called nonylphenol, which is a hormone disruptor can pass through containers. Nonylphenol is an environmental pollutant and is proven to affect sperm formation and also male reproductive system (7).
Polypropylene (PP)
Nonylphenol, which is a hormone disruptor, can be released from polypropylene (PP) plastic materials. Polypropylene is presented on plastic containers with the safety triangle code 5. Plastic cups are the most well-known products made with polypropylene. Margarine or butter containers, ketchup bottles, yoghurt containers can be produced with polypropylene. The effect of nonylphenol on the reproductive system was explained above.
In addition to the reproductive system, nonylphenol can also cause neurotoxicity, which is a condition that nerve cells are getting affected. Due to its neurotoxic effects, nonylphenol can cause calcium balance disorders and affects memory and learning capability (8).
Polystyrene (PS)
Benzene is used in the production of polystyrene (PS). Butadiene and styrene, which are the building blocks of polystyrene materials are known carcinogens. Disposable plastic plates and plastic cutlery are primarily made by this group. Foam cups that serve coffee in cafeterias are also made with polystyrene. Another chemical substance in the structure of polystyrene is 1,3-butadiene which is a carcinogen.
Others
Recycling triangle sign 7 contains all other plastic materials which can be recycled. The majority of the products in this group are made of polycarbonate (PC) plastics and contain bisphenol A (BPA). BPA has similar effects to the oestrogen hormone found in the human body. Its use in bottles for babies is prohibited in developed countries. It can cause nervous and behavioural disorders, especially in children. It is proved that it causes hormone-dependent prostate and breast cancers or accelerates the proliferation of cancer that has already started.
In the table below, we presented a summary of plastic products and their harmful effects on human health.
Type of plastic and recycling triangle number if any | Toxic substances and possible health effects |
Phthalates (Polyethylene terephthalate (PET) or PETE). Number 1 | Phthalates and nonylphenol are hormone disruptors. |
High-density polyethylene (HDPE). Number 2 | Nonylphenol is a hormone disruptor. |
Polyvinyl chloride (PVC-V). Number 3 | Vinyl chloride is a carcinogen. DEHA is a hormone disruptor and possible carcinogen. Phthalates are hormone disruptors. |
Low-density polyethylene (LDPE). Number 4 | Nonylphenol is a hormone disruptor. |
Polypropylene (PP). Number 5 | Nonylphenol is a hormone disruptor. |
Polystyrene (PS). Number 6 | Styrene is a carcinogen and a possible hormone disruptor. 1,3 butadiene is carcinogenic. Nonylphenol is a hormone disruptor. |
Polycarbonate (PC). Number 7 | Bisphenol A (BPA) is a hormone disruptor. |
Melamine and urea formaldehyde products | Formaldehyde is a carcinogen. Melamine is toxic to kidneys. |
Resin/polymeric coatings | DEHP is hormone disruptor. Acrylamide is a neurotoxic, genotoxic and possible carcinogen. |
Polyamides or nylon | Bisphenol A (BPA) is a hormone disruptor. |
How to avoid getting affected by plastic materials?
Here we listed several lifestyle changes to avoid getting affected by plastic materials to protect you and others around you.
- Do not drink water in plastic bottles. Try to use glass bottles instead. When exposed to direct sun, i.e., ultraviolet rays and heat, chemicals can dissolve from plastic and pass into the beverage more easily.
- Do not drink hot drinks in plastic cups.
- Do not stir/mix sugar in hot drinks with plastic straws.
- Use glass and stainless-steel containers to store food. Do not heat food in plastic containers in the microwave oven.
- Do not wash plastic containers in the dishwasher. Do not put your hot food and drinks on plates made of plastic material. Heat accelerates the formation of harmful chemicals.
- Do not consume canned food. Additives such as nitrite and nitrate are added to these foods to extend their shelf life and bisphenol A (BPA) is used to coat the inner layer of the cans.
- Prefer glass jars and fresh vegetables.
- Prefer baby’s bottles made of glass bottles. If it is made of plastic material, make sure it does not contain Bisphenol A (BPA).
- Use fabric curtains instead of nylon-type shower curtains. Do not let the chemicals to come out with the effect of hot water and harm you.
- Do not use polyvinyl chloride (PVC) materials in your home.
- Do not forget that the gaseous form chemicals will be released with the effect of heat and this will cause many health problems, especially cancer.
Conclusion
Plastic materials are categorised according to their ingredients and this is shown as numbers from 1 to 7 within the recycling triangle sign. The most dangerous element that results in the release of hazardous materials from plastics is heated. Serving hot meals in plastic containers has significantly decreased or been outlawed in developed nations. To lessen the negative consequences on the environment and human health, we should adopt modifications to our lifestyles that limit the usage of plastic materials.
8 Sources
- Food Research International https://pubmed.ncbi.nlm.nih.gov/29803455/
- Journal of Hazardous Materials https://pubmed.ncbi.nlm.nih.gov/28800814/
- Polymers https://pubmed.ncbi.nlm.nih.gov/34202594/
- Wiener klinische Wochenschrift https://pubmed.ncbi.nlm.nih.gov/23334477/
- Journal of Hepatology https://pubmed.ncbi.nlm.nih.gov/19836850/
- World Journal of Gastroenterology https://pubmed.ncbi.nlm.nih.gov/31543680/
- Andrologia https://pubmed.ncbi.nlm.nih.gov/32662580/
- Current Neuropharmacology https://pubmed.ncbi.nlm.nih.gov/33213348/